Mechanical timepiece

Abstract

To provide a mechanical timepiece for improving rate accuracy.SOLUTION: The mechanical timepiece 1 includes the speed control mechanism 30, the escapement mechanism 20, the permanent magnet 41 that rotates forward and backward together with the balance wheel 31, the coil 43 in which a counter electromotive voltage is generated according to the forward and backward rotation of the permanent magnet 41, and the detection circuit 45 that detects the detection signal DE based on the counter electromotive voltage. When the detection timing of the detection signal DE is delayed from the predetermined reference timing, the control circuit 44 sets the braking force to the first braking force that causes the impulse pin 312a to collide with the pallet fork 22 when at least one of the motions of the impulse pin 312a in the forward direction and the reverse direction is switched to the other motion. 312a.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a mechanical timepiece. [Background technology]

[0002] Patent Document 1 below discloses a mechanical timepiece that generates electricity by providing a permanent magnet that rotates integrally with the balance wheel, and adjusts the rate based on the back electromotive force generated in response to the rotation of the permanent magnet. In the mechanical timepiece of Patent Document 1, if the rate is fast, control is performed to slow down the rotation, and if the rate is slow, control is performed to speed up the rotation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 176378 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention have been studying how to adjust the rate of a mechanical timepiece with adjustable rate with greater accuracy.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to provide a mechanical timepiece that improves rate accuracy. [Means for solving the problem]

[0006] (1) A mechanical timepiece comprising: a regulating mechanism including a rotating body that rotates in forward and reverse directions; an escapement mechanism including an escape wheel and an anchor that drives the escape wheel by the collision of an impulse jewel that rotates in forward and reverse directions in accordance with the forward and reverse rotation of the rotating body; a permanent magnet that rotates in forward and reverse directions together with the rotating body; a coil that generates a back electromotive force in accordance with the forward and reverse rotation of the permanent magnet; a detection circuit that detects a detection signal based on the back electromotive force; and a control circuit that controls the forward and reverse rotation of the impulse jewel by setting a braking force that brakes the permanent magnet based on the detection timing of the detection signal, wherein, if the detection timing is delayed from a predetermined reference timing, the control circuit sets the braking force to a first braking force that causes the impulse jewel to collide with the anchor when at least one of the forward and reverse directions of the impulse jewel switches to the other.

[0007] (2) In (1), when the detection timing is ahead of the reference timing, the control circuit sets the braking force to a second braking force that prevents the impulse jewel from colliding with the pallet when at least one of the forward and reverse movements of the impulse jewel switches to the other movement.

[0008] (3) In the mechanical timepiece according to (1) or (2), the reference timing is the output timing of a reference signal that is periodically output from a reference signal source.

[0009] (4) In (3), the control circuit sets the braking force to the first braking force when the delay of the detection timing relative to the output timing is equal to or greater than a predetermined value, and sets the braking force to the second braking force when the advance of the detection timing relative to the output timing is equal to or greater than a predetermined value.

[0010] (5) In any of (1) to (4), the impulse jewel rotates in both directions so that the rotation angle is positive or negative, with the power supply position where power is periodically supplied from a power source being the 0° position, and the control circuit sets the braking force in a unit period where the rotation angle of the impulse jewel is positive, and the braking force in a unit period where the rotation angle of the impulse jewel is negative, respectively.

[0011] (6) In any one of (1) to (5), the pallet fork includes a first collision target portion against which the impulse jewel rotating in the forward direction collides, and a second collision target portion against which the impulse jewel rotating in the reverse direction collides, and the first collision target portion and the second collision target portion have asymmetric shapes.

[0012] (7) In (6), a mechanical timepiece in which either the first impacted portion or the second impacted portion includes a shape that extends along the rotation trajectory of the impulse jewel so as to regulate the amplitude of the impulse jewel.

[0013] (8) In the mechanical timepiece of (6) or (7), either one of the first collision part and the second collision part is configured so that the impulse jewel collides when the movement of one of the impulse jewels switches to the movement of the other, regardless of whether the braking force is set to the first braking force or the second braking force.

[0014] (9) In (7), the mechanical timepiece, when the detection timing is delayed from the reference timing, the control circuit sets the braking force to the first braking force that causes the impulse jewel to collide with the other of the first collision-receiving part and the second collision-receiving part when the one movement of the impulse jewel switches to the other movement. [Effects of the Invention]

[0015] According to the above aspects (1) to (9) of the present invention, it is possible to provide a mechanical timepiece that improves rate accuracy. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is an exploded perspective view showing the base plate and the components assembled thereto. [Figure 2] FIG. 2 is a perspective view showing the escapement mechanism, the governor, and the surrounding components. [Figure 3] FIG. 1 is a block diagram showing the overall configuration of a mechanical timepiece. [Figure 4] 10A and 10B are diagrams for explaining a back electromotive force detected by a coil in accordance with rotation of a permanent magnet. [Figure 5A] 10A and 10B are diagrams for explaining the movement of the swing stone in the second control of the first embodiment. [Figure 5B] 10A and 10B are diagrams for explaining the operation of the swing stone in the first control of the first embodiment. [Figure 6] FIG. 4 is a diagram showing the relationship between the rotation angle of the balance wheel and the back electromotive force in the first embodiment. [Figure 7] FIG. 3 is a diagram for explaining braking control in the first embodiment. [Figure 8] FIG. 3 is a diagram showing a control processing flow in the first embodiment. [Figure 9] FIG. 10 is a diagram showing a control processing flow in a first modified example. [Figure 10] FIG. 10 is a diagram showing a control processing flow in a second modified example. [Figure 11A] 10A and 10B are diagrams for explaining the operation of the swing stone in the first control and the second control of the second embodiment. [Figure 11B] 10A and 10B are diagrams for explaining the operation of the swing stone in the second control of the second embodiment. [Figure 12] FIG. 10 is a diagram showing the relationship between the rotation angle of the balance wheel and the back electromotive force in the second embodiment. [Figure 13] FIG. 10 is a diagram for explaining braking control in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.

[0018] The overall configuration of the mechanical timepiece 1 will be described with reference to Figures 1 to 5B. As shown in Figure 2, the mechanical timepiece 1 is equipped with a power spring 11, an escapement mechanism 20, a speed regulating mechanism 30, and hands 131. Power from the power spring 11 is transmitted to the escapement mechanism 20 and the speed regulating mechanism 30 through a train wheel 12. Each of these members and mechanisms is incorporated into a main plate 10.

[0019] The escapement mechanism 20 continuously applies a force for reciprocating motion to the balance wheel 31 included in the regulating mechanism 30, and rotates each gear in the wheel train 12 at a constant speed by regular vibrations from the balance wheel 31. As shown in FIG. 2, the escapement mechanism 20 includes an escape wheel 21 and an anchor 22. In this embodiment, the balance wheel 31 is designed to perform one reciprocating motion every two seconds, and the escape wheel 21 is configured to perform one step motion every second.

[0020] 1 and 2, the speed regulating mechanism 30 includes a balance wheel 31 and a hairspring 32. The balance wheel 31 is supported so as to be rotatable in both forward and reverse directions around a balance stem 311, which is the axis of rotation. The balance stem 311 is provided with an impulse seat 312 to which an impulse jewel 312a is fixed.

[0021] The hairspring 32 is spiral-shaped, and its outer end is fixed to a hairspring holder 34 (see FIG. 1), and its inner end is fixed to a balance arbour 311. The speed-governing mechanism 30 uses the expansion and contraction movement (elastic deformation) of the hairspring 32 to repeatedly rotate the balance wheel 31 forward and backward (reciprocating motion) at a constant cycle.

[0022] In the first embodiment, the hairspring 32 is made of a resin material with a low Young's modulus. This allows the balance wheel 31 to oscillate at a slower speed than when the hairspring 32 is made of a metal material. Also, in the first embodiment, the rotation angle [deg] of the balance wheel 31 when the hairspring 32 is in the neutral position (natural length position) of elastic deformation is set to 0°. Power is supplied from the power spring 11 to the balance wheel 31 when the hairspring 32 is in the vicinity of the neutral position of elastic deformation. In other words, the 0° position is the power supply position.

[0023] As shown in Figures 5A and 5B, the pallet fork 22 has an pallet fork stem 221 which is the rotation axis, a rod portion 222 which includes a tip portion called a stag beetle, a first arm portion 223 to which an inward claw 223a which hits the escape wheel 21 is attached, and a second arm portion 224 which extends in the opposite direction of the first arm portion 223 and to which an outward claw 224a which hits the escape wheel 21 is attached.

[0024] The stag beetle shape of the pallet fork 22 has a collision receiving portion 2221 and a collision receiving portion 2222 that the impulse jewel 312a collides with. The collision receiving portion 2221 and the collision receiving portion 2222 are spaced apart from each other, and when the impulse jewel 312a collides with their inner surfaces, the pallet fork 22 is driven around the pallet fork axon 221 as the center of rotation.

[0025] For example, when the impulse jewel 312a located at the position shown in Fig. 5A passes the 0° position by rotating clockwise, the impulse jewel 312a collides with the inner surface of the collision receiving portion 2221, and the pallet fork 22 is driven counterclockwise around the pallet fork stem 221 as the rotation center. This releases the escape wheel 21 from being stopped by the extending pawl 224a, and the escape wheel 21 begins to drive.

[0026] Furthermore, the mechanical timepiece 1 is equipped with a rate adjustment means 40. The rate adjustment means 40 has a permanent magnet 41, a stator 42, and a coil 43 shown in Fig. 2 etc., and a control circuit 44, a detection circuit 45, a frequency divider circuit 47, an oscillation circuit 48, and a braking circuit 80 shown in Fig. 3.

[0027] The permanent magnet 41 is a bipolar magnetized disk-shaped rotating body, and as shown in Fig. 4, has an N-pole portion 411 and an S-pole portion 412 magnetized in the radial direction to N-pole and S-pole. An insertion hole through which the balance stem 311 is inserted is formed in the center of the permanent magnet 41. The permanent magnet 41 rotates forward and backward together with the balance wheel 31 so that the rotation angle of the permanent magnet 41 is the same as the rotation angle of the balance wheel 31 in accordance with the forward and reverse rotation of the balance wheel 31 (balance stem 311).

[0028] The stator 42 is made of a soft magnetic material and includes a first magnetic portion 421 having a first end 421a and a second magnetic portion 422 having a second end 422a, and forms a magnetic circuit together with the coil 43. The stator 42 is provided so that a magnetic torque is generated with respect to the permanent magnet 41 in accordance with the rotation angle of the permanent magnet 41.

[0029] The control circuit 44 controls the operation of each circuit included in the rate adjusting means 40. The control circuit 44 sets the braking force for braking the permanent magnet 41 by controlling the braking circuit 80. The braking force is applied to the permanent magnet 41, for example, by an electromagnetic brake. The electromagnetic brake is preferably an induced electromotive force that generates a magnetic field in a direction that prevents a change in the magnetic flux generated in the coil 43 as the permanent magnet 41 rotates by short-circuiting the first and second terminals of the coil 43 to create a closed loop.

[0030] The detection circuit 45 detects the detection signal DE based on the voltage waveform generated in the coil 43 due to the movement of the permanent magnet 41. The detection signal DE detected by the detection circuit 45 is input to the control circuit 44. The detection signal DE may be detected by the detection circuit 45 when a back electromotive force equal to or greater than a predetermined threshold Vth is generated. In the first embodiment, the detection signal DE is a pulse signal synchronized with the start timing of a unit cycle of the back electromotive force. Here, the start timing of the unit cycle is the timing when the balance wheel 31 passes through the 0° position, which corresponds to the zero-crossing point where the back electromotive force switches from negative to positive. The detection signal that is the start timing of the unit cycle may be determined, for example, by setting a non-determination period during which a zero-crossing point other than the start timing of the unit cycle where the back electromotive force switches from negative to positive is not determined to be a detection signal.

[0031] The predetermined threshold Vth is preferably a value near 0 [V], for example, +10 [mV]. Note that noise may momentarily occur near the threshold Vth of 0 [V] due to external factors such as impact. To avoid false detection due to such noise, for example, the timing for determining the detection signal DE for rotation detection may be set to any timing when the detection signal DE is detected two or more times in succession (for example, the timing when it was last detected). Furthermore, the detection signal DE is a pulse signal synchronized with the timing when the back electromotive force switches from positive to negative, and may be detected by the detection circuit 45 when a back electromotive force less than the predetermined threshold -Vth occurs.

[0032] The oscillator circuit 48 outputs a predetermined oscillation signal based on the frequency of the crystal oscillator 70. The frequency divider circuit 47 divides the oscillation signal output from the oscillator circuit 48. By dividing the oscillation signal based on the crystal oscillator 70, the frequency divider circuit 47 generates a reference signal OS that is output at intervals corresponding to the unit period of the back electromotive force. The output timing of the reference signal OS is set in advance so as to correspond to the detection signal DE that is detected when there is neither an advance nor a delay in the forward or reverse rotational motion of the balance wheel 31. In this embodiment, the reference signal OS is output approximately every 500 ms.

[0033] The mechanical timepiece 1 has a power generation function that uses the principle of electromagnetic induction. In the first embodiment, the regulating mechanism 30 functions as part of the generator. Specifically, the permanent magnet 41 rotates forward and backward as the balance wheel 31 rotates forward and backward, and electricity is generated by the current that is generated in the coil 43 based on the change in the magnetic field caused by the movement of the permanent magnet 41. The power extracted using this operating principle is used to start the power supply circuit 60. When the power supply circuit 60 is started, the control circuit 44 can be driven.

[0034] Rectifier circuit 50 rectifies the current generated in coil 43 due to the movement of permanent magnet 41 accompanying the forward and reverse rotation of balance wheel 31 of speed regulating mechanism 30. Power supply circuit 60 includes, for example, a capacitor, and stores power for driving control circuit 44 based on the current rectified by rectifier circuit 50.

[0035] The rate adjusting means 40 shown in FIG. 3 is an example, and is not limited to the illustrated configuration as long as it can realize the above-mentioned functions.

[0036] The relationship between the rotation angle of the permanent magnet 41 and the back electromotive force will be described with reference to Fig. 4. Here, as a comparative example, an example will be described in which the swing angle (maximum angle) of the balance wheel 31 is preset to ±340°.

[0037] The counter electromotive force generated in the coil 43 due to a change in the magnetic field when the N-pole portion 411 of the permanent magnet 41 moves in a direction toward the first end 421a of the stator 42 is defined as a "positive" counter electromotive force. The counter electromotive force generated in the coil 43 due to a change in the magnetic field when the N-pole portion 411 moves in a direction away from the first end 421a of the stator 42 is defined as a "negative" counter electromotive force.

[0038] At the 0° position, the permanent magnet 41 is in a position of magnetic balance, and the back electromotive force generated in the coil 43 is zero. At the 0° position, the permanent magnet 41 is supplied with power from the power spring 11. Furthermore, while the permanent magnet 41 rotates from the 0° position toward the 180° position, the N pole portion 411 moves in a direction approaching the first end 421a. Therefore, while the permanent magnet 41 rotates from the 0° position toward the 180° position, a positive back electromotive force is generated in the coil 43.

[0039] Since the permanent magnet 41 is in a position of magnetic balance at the 0° position, it is also in a position of magnetic balance at the 180° position, and the back electromotive force generated in the coil 43 is zero. When the permanent magnet 41 rotates from the 180° position toward the 340° position, the N pole portion 411 moves in a direction away from the first end 421a. Therefore, a negative back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from the 180° position toward the 340° position.

[0040] The angular velocity of the permanent magnet 41 becomes zero at the 340° position, which is the turning point of the reciprocating motion. Therefore, at the 340° position, the back electromotive force generated in the coil 43 becomes zero. When the permanent magnet 41 reaches the 340° position, the elastic force of the hairspring 32 causes the permanent magnet 41 to start rotating toward the 180° position. When the permanent magnet 41 rotates from the 340° position toward the 180° position, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, a positive back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from the 340° position toward the 180° position.

[0041] When the permanent magnet 41 rotates from the 180° position to the 0° position, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, when the permanent magnet 41 rotates from the 180° position to the 0° position, a negative counter electromotive force is generated in the coil 43.

[0042] Power is supplied from the power spring 11 to the permanent magnet 41 that has reached the 0° position. While the permanent magnet 41 rotates from the 0° position toward the −180° position, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, when the permanent magnet 41 rotates from the 0° position toward the −180° position, a positive counter electromotive force is generated in the coil 43.

[0043] Just as the permanent magnet 41 is in a magnetically balanced position at the 180° position, it is also in a magnetically balanced position at the −180° position, and the back electromotive force generated in the coil 43 is zero when the permanent magnet 41 is in the −180° position. When the permanent magnet 41 rotates from the −180° position to the −340° position, the N pole portion 411 moves in a direction away from the first end 421a. Therefore, a negative back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from the −180° position to the −340° position.

[0044] The angular velocity of the permanent magnet 41 becomes zero at the −340° position, which is the turning point of the reciprocating motion. Therefore, the back electromotive force generated in the coil 43 becomes zero at the −340° position. When the permanent magnet 41 reaches the −340° position, the elastic force of the hairspring 32 causes the permanent magnet 41 to start rotating toward the −180° position. When the permanent magnet 41 rotates from the −340° position toward the −180° position, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, a positive back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from the −340° position toward the −180° position.

[0045] When the permanent magnet 41 rotates from the -180° position to the 0° position, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, when the permanent magnet 41 rotates from the -180° position to the 0° position, a negative counter electromotive force is generated in the coil 43.

[0046] The above-described operation is repeated, and when there is neither advance nor delay in the forward or reverse rotational motion of the balance wheel 31 (permanent magnet 41), a back electromotive force shown in FIG.

[0047] Next, details of braking control by the control circuit 44 in the first embodiment will be described with reference to Figures 5A to 8. In the following description, the counterclockwise direction in Figures 5A and 5B is defined as the positive direction, and the clockwise direction is defined as the negative direction. The rotation angle of the impulse jewel 312a coincides with the rotation angles of the balance wheel 31 and the permanent magnet 41.

[0048] In the first embodiment, the control circuit 44 sets the braking force based on the difference between the output timing of the reference signal OS and the detection timing of the detection signal DE. When the difference t calculated by subtracting the detection timing of the detection signal DE from the output timing of the reference signal OS is equal to or greater than 0, the control circuit 44 determines that the rate is "leading" and increases the braking force applied by the electromagnetic brake DB to slow the rate. When the difference t is less than 0, the control circuit 44 determines that the rate is "lagging" and decreases the braking force applied by the electromagnetic brake DB to speed up the rate. The electromagnetic brake DB outputs multiple consecutive single pulses, and the strength of the braking force can be switched by adjusting the length of the single pulses and the output interval between the single pulses (duty ratio).

[0049] In the comparative example described above with reference to Fig. 4, the case where the balance wheel 31 rotates forward and backward at an ideal frequency has been described. Rate accuracy can be maintained by operating the balance wheel 31 ideally. However, the operation of the balance wheel 31 tends to become unstable near the turning point of the forward and backward rotational motion where the rotation speed is low, which can make it difficult to maintain rate accuracy.

[0050] Therefore, in the first embodiment, a configuration is adopted in which the impulse jewel 312a is caused to collide with the outer surfaces of the collision-receiving portions 2221, 2222 of the pallet fork 22, thereby causing the impulse jewel 312a to repel from the pallet fork 22 and stabilizing the operation of the balance wheel 31 near the turning point in the forward and reverse rotational motion.

[0051] Specifically, the control circuit 44 performs a first control in which the braking force for braking the permanent magnet 41 is set to a first braking force, and a second control in which the braking force for braking the permanent magnet 41 is set to a second braking force greater than the first braking force. In the first embodiment, the duty ratio of the first braking force is set to 4 / 16, and the duty ratio of the second braking force is set to 12 / 16. However, this is not limited thereto, and the first braking force may be large enough so that the impulse jewel 312a collides with the outer surfaces of the collision-receiving portions 2221, 2222 of the pallet fork 22 when at least one of the forward and reverse directions of the impulse jewel 312a switches to the other. The second braking force may be large enough so that the impulse jewel 312a does not collide with the outer surfaces of the collision-receiving portions 2221, 2222 of the pallet fork 22 when at least one of the forward and reverse directions of the impulse jewel 312a switches to the other.

[0052] The first braking force in the first control is preferably strong enough to cause impulse jewel 312a to collide with collision target parts 2221, 2222 when power spring 11, the power source, is fully wound. The second braking force in the second control is preferably strong enough to prevent impulse jewel 312a from colliding with collision target parts 2221, 2222, regardless of the state of winding of power spring 11, the power source.

[0053] As shown in unit cycle (1) of FIG. 7, when the detection timing of the detection signal DE is delayed from the reference timing of the reference signal OS, the control circuit 44 sets the braking force to the first braking force in order to advance the rate.

[0054] The permanent magnet 41 is braked by the first braking force with a small duty ratio, thereby increasing the swing angle of the impulse jewel 312a. FIG. 5B shows the manner in which the impulse jewel 312a collides with the outer surface of the pallet fork 22 under the first control. Under the first control, the impulse jewel 312a, rotating in the forward direction, collides with the outer surface of the impacted portion 2221 at the +330° position shown in FIG. 5B, and is repelled by the collision, causing it to move in the opposite direction. At this time, the rotation direction of the impulse jewel 312a (balance wheel 31) quickly reverses (see FIG. 6), and the back electromotive force rises sharply (see FIGS. 6 and 7). Under the first control, the repulsion caused by the collision allows the rate to be further advanced. Furthermore, the repulsion caused by the collision stabilizes the operation of the balance wheel 31 before and after the turnaround.

[0055] On the other hand, as shown in unit cycle (2) of Figure 7, when the detection timing of the detection signal DE is ahead of the reference timing of the reference signal OS, the control circuit 44 sets the braking force to the second braking force in order to slow down the pace.

[0056] Because the permanent magnet 41 is braked by the second braking force with a large duty ratio, the swing angle of the impulse jewel 312a is smaller than when the permanent magnet 41 is controlled by the first braking force. FIG. 5A shows how, under second control, the impulse jewel 312a does not collide with the outer surface of the pallet fork 22. Under second control, the impulse jewel 312a, rotating in the forward direction, reaches the +270° position shown in FIG. 5A and then moves in the reverse direction without colliding with the outer surface of the collision target 2221. At this time, the rotation direction of the impulse jewel 312a is gradually reversed (see FIG. 6), and the back electromotive force rises smoothly (see FIGS. 6 and 7). Furthermore, under second control, no repulsion due to collision occurs, making it possible to further slow the rate.

[0057] Next, the control process flow in the first embodiment will be described with reference to Figure 8. First, the power supply circuit 60 is started by generating electricity through the movement of the permanent magnet 41 (Y in S1). After the first detection signal DE is detected by the rotation detection circuit 45 (Y in S2), the control circuit 44 performs braking control based on the current braking force (S3). Note that the braking force after the first detection signal DE is detected may be set to either the first braking force or the second braking force. Furthermore, it is preferable that braking control be performed using the currently set braking force until the next detection signal DE is detected (N in S4).

[0058] When the next detection signal DE is detected (Y in S4), the control circuit 44 calculates the deviation amount t of the detection signal DE (S5). When the deviation amount t is less than 0 (N in S6), the control circuit 44 sets the current braking force to the first braking force (S7) and performs the first control (S3). As a result, the impulse jewel 312a collides with the outer surface of the collision receiving portion 2221 or the collision receiving portion 2222, thereby switching its rotation direction. When the deviation amount t is 0 or greater (Y in S6), the control circuit 44 sets the current braking force to the second braking force (S8) and performs the second control (S3). As a result, the impulse jewel 312a switches its rotation direction without colliding with the outer surface of the collision receiving portion 2221 or the collision receiving portion 2222.

[0059] In the mechanical timepiece 1 according to the first embodiment described above, the movement of the balance wheel 31 can be stabilized, making it easy to adjust the advance and delay, thereby improving the rate accuracy.

[0060] Next, a first modified example of the first embodiment will be described with reference to FIG. 9. Note that the same processes as those described with reference to FIG. 8 are designated by the same reference numerals, and their description will be omitted. In the first modified example, when the delay in the detection timing of the detection signal DE relative to the output timing of the reference signal OS is equal to or greater than a predetermined value (when the negative amount is large), the braking force is set to the first braking force, and when the advance in the detection timing of the detection signal DE relative to the output timing of the reference signal OS is equal to or greater than a predetermined value, the braking force is set to the second braking force. Specifically, the reference timing when set to the first braking force is a timing (+x seconds) that is advanced by a predetermined time from the output timing of the reference signal OS, and the reference timing when set to the second braking force is a timing (-y seconds) that is delayed by a predetermined time from the output timing of the reference signal OS. The first modified example can be considered an example in which the first control is maintained when the detection signal DE advances relative to the reference signal OS but the advance is small, and the second control is maintained when the detection signal DE lags relative to the reference signal OS but the delay is small.

[0061] In the first modification, after the first detection signal DE is detected by the rotation detection circuit 45 (Y in S2), the first control is performed based on the first braking force (S13). Then, if the deviation amount t of the next detected detection signal DE is less than +x seconds (N in S4, S5, S16), the first control is continued (S13). That is, even if the deviation amount t is positive and there is an advance compared to the reference signal OS, if the advance amount is small, the first control is continued without switching to the second control. In the first control, a repulsion caused by a collision can further advance the rate. Furthermore, the repulsion caused by a collision stabilizes the operation of the balance wheel 31 before and after the turning point.

[0062] If the deviation amount t is +x seconds or more (Y in S16), the control circuit 44 sets the braking force to the second braking force and performs the second control (S17). Then, if the deviation amount t of the next detected detection signal DE is greater than -y seconds (N in S18, S19, and S110), the control circuit 44 continues the second control (S17). In other words, even if the deviation amount t is negative and there is a delay with respect to the reference signal OS, if the delay is small, the control circuit 44 does not switch to the first control and continues the second control. In the second control, no repulsion due to collision occurs, so it is possible to further slow down the pace.

[0063] On the other hand, if the deviation t of the next detected detection signal DE is less than -y seconds (Y in S18, S19, S110), the delay is large, so the control is switched to the first control (S13). Note that the absolute value of y may be the same as or different from the absolute value of x.

[0064] In the first modified example, the frequency of switching the braking force can be reduced. Therefore, by lengthening the period in which the balance wheel 31 rotates at a continuous high frequency and the period in which the balance wheel 31 rotates at a continuous low frequency, the balance wheel 31 can be made to move in a distinctive manner. Furthermore, by utilizing the collision of the impulse jewel 312a with the collision receiving portions 2221 and 2222, it is possible to maintain rate accuracy as in the first embodiment. Note that in the first modified example, it is preferable to make the dial transparent or to form an opening in the dial so that the balance wheel 31 can be seen by the user.

[0065] Next, a second modified example of the first embodiment will be described with reference to FIG. 10. Note that the same processes as those described with reference to FIG. 8 are designated by the same reference numerals, and their description will be omitted. In the second modified example, an example will be described in which the control circuit 44 sets the braking force in a unit period in which the rotation angle of the impulse jewel 312a is positive, and the braking force in a unit period in which the rotation angle of the impulse jewel 312a is negative. Note that the initial braking force in the control A and control B described below may be set in advance. For example, the initial braking force in the control A and control B may be a first braking force. That is, after the first detection signal DE is detected, a first control based on the first braking force may be performed in the first unit period and the next unit period.

[0066] In the second modified example, after the first detection signal DE is detected by the rotation detection circuit 45 (Y in S2), control A is performed (S23). Control A may be performed, for example, in a unit cycle in which the rotation angle of the balance wheel 31 is positive. Then, if the deviation t_A of the next detected detection signal DE is less than 0 (N in S24, S25, S26), the braking force of control A is set to the first braking force (S27). On the other hand, if the deviation t_A is 0 or greater (Y in S24, S25, S26), the braking force of control A is set to the second braking force (S28).

[0067] Thereafter, control B is performed (S29). Control B is preferably performed in a unit cycle in which the rotation angle of the balance wheel 31 is negative. Then, if the deviation t_B of the subsequently detected detection signal DE is equal to or greater than 0 (Y in S210, S211, and S212), the braking force of control B is set to the second braking force (S214). On the other hand, if the deviation t_B is less than 0 (N in S210, S211, and S212), the braking force of control B is set to the first braking force (S213).

[0068] Thereafter, Control A is performed based on the braking force set in S27 or S28 (S23). When the first braking force is set in S27, Control A is the first control, and a rebound due to a collision occurs, allowing the rate to be further advanced. Furthermore, the rebound due to a collision stabilizes the operation of the balance wheel 31 before and after the turnaround. On the other hand, when the second braking force is set in S28, Control A is the second control, and no rebound due to a collision occurs, allowing the rate to be further delayed.

[0069] Furthermore, after the processes of S24 to S28, control B is performed based on the braking force set in S213 or S214 (S29).

[0070] In the second modified example, the balance wheel 31 can be adjusted to different vibration frequencies when the rotation angle is positive and when it is negative, allowing the balance wheel 31 to have a distinctive movement. Furthermore, by utilizing the impact of the impulse jewel 312a on the impacted portions 2221 and 2222, rate accuracy can be maintained, as in the first embodiment. In the second modified example, the dial may be made transparent or an opening may be formed in the dial so that the balance wheel 31 can be viewed by the user. Furthermore, in the second modified example, an example in which control is alternately switched every unit cycle has been described, but the present invention is not limited to this, and control may be alternately switched every any number of unit cycles.

[0071] Next, a second embodiment will be described with reference to Figures 11A to 13. In the second embodiment, as shown in Figures 11A and 11B, the collision receiving portion 2221A and the collision receiving portion 2222 have asymmetric shapes. Specifically, the collision receiving portion 2221A is longer than the collision receiving portion 2222. With this configuration, when the impulse jewel 312a switches from the forward direction to the reverse direction of motion, the impulse jewel 312a will collide with the collision receiving portion 2221A regardless of whether the control circuit 44 is performing the first control or the second control.

[0072] In the second embodiment, detection of the detection signal DE and switching of the braking control based thereon are performed for two cycles of the unit cycle described in the first embodiment, thereby preventing unnecessary switching of the braking force.

[0073] The impact receiving portion 2221A has a shape that extends along the rotation trajectory of the impulse jewel 312a so as to restrict the swing angle of the impulse jewel 312a when it is in a position when it impacts. The impact receiving portion 2221A may also have a tip surface that the impulse jewel 312a impacts. The impact receiving portion 2221A may be formed by extending the stag beetle of a general-purpose pallet fork, or by attaching a separate part to the stag beetle. The impact receiving portion 2222 may have a shape similar to that shown in the first embodiment.

[0074] FIG. 11A shows the state in which the impulse jewel 312a, rotating in the forward direction, reaches the +255° position, collides with the tip surface of the collision target 2221A, rebounds, and begins to rotate in the reverse direction. As shown in FIGS. 12 and 13, when the impulse jewel 312a switches from forward to reverse motion, it always collides with the collision target 2221A at the +255° position, at which point the back electromotive force rises sharply. Furthermore, in the first control, in which the braking force is small, the impulse jewel 312a collides more strongly with the collision target 2221A, resulting in a larger rebound force, compared to the second control, in which the braking force is large. Therefore, in the first control, the rate can be increased significantly compared to the second control.

[0075] 11B shows how, in the second control with a large braking force, the impulse jewel 312a rotating in the reverse direction reaches the -315° position and starts to rotate in the forward direction without colliding with the outer surface of the collision receiving portion 2222. Also, although not shown, in the first control with a small braking force, the impulse jewel 312a rotating in the reverse direction reaches the -330° position, as in the first embodiment, collides with the outer surface of the collision receiving portion 2222, and rebounds, rotating in the forward direction.

[0076] 12 and 13 show an example in which the impulse jewel 312a switches from reverse to forward movement at the -330° position in unit cycle (1) in which the first control is performed, and an example in which the impulse jewel 312a switches from reverse to forward movement at the -315° position in unit cycle (2) in which the second control is performed.

[0077] In the second embodiment, it is also possible to control whether or not to collide the impulse jewel 312a with the collision target 2222 only when the impulse jewel 312a switches from the reverse direction to the forward direction of motion. Also, the unit period may be set in the same way as in the first embodiment. That is, the detection signal DE may be detected even when the impulse jewel 312a rotating in the reverse direction passes through the 0° position, and the braking force may be switched based on the amount of deviation.

[0078] Furthermore, by making the impact receiving portion 2222 symmetrical in shape to the impact receiving portion 2221A, it is possible to repel the impulse jewel 312a with high frequency, and to further stabilize the operation of the balance wheel 31. However, in this case, the time required to brake the permanent magnet 41 becomes shorter, which may in turn result in a decrease in rate accuracy. In the second embodiment, by lengthening only the impact receiving portion 2221A, it is possible to ensure the time required to brake the permanent magnet 41.

[0079] Furthermore, in the second embodiment, if the rate deviates significantly in the forward direction due to disturbance or the like, the impulse jewel 312a will collide strongly with the collision target 2221A and be repelled, but because the length of the collision target 2222 is short, there is sufficient time to brake the permanent magnet 41. Therefore, even if a disturbance occurs, the rate accuracy can be maintained.

[0080] In the second embodiment described above, the chances of rebounding due to the impact of the impulse jewel 312a can be increased, thereby making the operation of the balance wheel 31 more stable.

[0081] In the second embodiment, it is also possible to control whether or not to collide the impulse jewel 312a with the collision target portion 2221A. In other words, the impulse jewel 312a does not have to always collide with the collision target portion 2221A in a unit cycle.

[0082] The swing angle of the impulse jewel 312a described in the above embodiments is merely an example and is not limited to the described angle. Furthermore, the duty ratios of the first braking force and the second braking force described in the above embodiments are merely an example and are not limited to the described magnitudes. The duty ratio of the first braking force in the first control may be 0. Furthermore, the braking forces in the first control and the second control may be set to a plurality of values ​​depending on the deviation amount t. For example, in the first control, the duty ratio may be set to either 4 / 16 or 2 / 16 depending on the deviation amount t in the lead direction. Furthermore, in the second control, the duty ratio may be set to either 12 / 16 or 14 / 16 depending on the deviation amount t in the lag direction.

[0083] Furthermore, the rotating body that rotates forward and backward in accordance with the forward and backward rotation of the balance stem 311 does not need to have the balance wheel 31, but may have at least the balance stem 311 and the impulse jewel 312a that rotates together with the balance stem 311. Furthermore, as long as it is configured to allow braking control (rate adjustment), it is not limited to an electromagnetic brake, and for example, the permanent magnet 41 may be braked by a speed control pulse. [Explanation of symbols]

[0084] 1 mechanical watch, 10 main plate, 11 power spring, 12 wheel train, 131 pointer, 20 escapement mechanism, 21 escape wheel, 22 anchor, 221 anchor post, 222 rod portion, 2221, 2222 impact-receiving portion, 30 regulating mechanism, 31 balance wheel, 311 balance post, 312 impulse seat, 312a impulse jewel, 32 balance spring, 34 balance holder, 40 rate adjusting means, 41 permanent magnet, 42 stator, 421 first magnetic portion, 421a first end, 422 second magnetic portion, 422a second end, 43 coil, 44 control circuit, 45 detection circuit, 47 frequency divider circuit, 48 oscillation circuit, 50 rectifier circuit, 60 power supply circuit, 70 quartz crystal oscillator, 80 braking circuit.

Claims

1. a speed control mechanism including a rotating body that rotates in both directions; an escapement mechanism including an escape wheel and an anchor that drives the escape wheel by collision of an impulse jewel that rotates in both directions in accordance with the rotation of the rotor; a permanent magnet that rotates in both directions together with the rotor; a coil in which a counter electromotive force is generated in response to the forward and reverse rotational motion of the permanent magnet; a detection circuit that detects a detection signal based on the back electromotive force; a control circuit for controlling the forward and reverse rotation of the impulse pin by setting a braking force for braking the permanent magnet based on the detection timing of the detection signal; and The control circuit If the detection timing is later than a predetermined reference timing, the braking force is set to a first braking force that causes the impulse jewel to collide with the pallet fork when at least one of the forward and reverse motions of the impulse jewel switches to the other motion. Mechanical watch.

2. The control circuit If the detection timing is earlier than the reference timing, the braking force is set to a second braking force that prevents the impulse jewel from colliding with the pallet fork when at least one of the forward and reverse direction movements of the impulse jewel is switched to the other movement.

2. The mechanical timepiece according to claim 1.

3. the reference timing is an output timing of a reference signal that is periodically output from a reference signal source; 3. The mechanical timepiece according to claim 1 or 2.

4. The control circuit If the delay amount of the detection timing relative to the output timing is equal to or greater than a predetermined value, the braking force is set to the first braking force; When the advance amount of the detection timing relative to the output timing is equal to or greater than a predetermined value, the braking force is set to the second braking force.

4. The mechanical timepiece according to claim 3.

5. The impulse jewel rotates in a forward and reverse direction so that the rotation angle becomes positive or negative, with a power supply position where power is periodically supplied from a power source being set as a 0° position, the control circuit sets the braking force in a unit period when the rotation angle of the impulse pin is positive, and the braking force in a unit period when the rotation angle of the impulse pin is negative, 3. The mechanical timepiece according to claim 1 or 2.

6. The pallet fork includes a first collision receiving portion that is collided with by the impulse jewel rotating in the forward direction, and a second collision receiving portion that is collided with by the impulse jewel rotating in the reverse direction, The first collision target portion and the second collision target portion have asymmetric shapes.

2. The mechanical timepiece according to claim 1.

7. One of the first impacted portion and the second impacted portion includes a shape extending along a rotation trajectory of the impulse stone so as to regulate the amplitude of the impulse stone.

7. The mechanical timepiece according to claim 6.

8. Either the first collision receiving portion or the second collision receiving portion is provided so that the impulse stone collides with the first collision receiving portion when the motion of the impulse stone switches to the other motion, regardless of whether the braking force is set to the first braking force or the second braking force.

7. The mechanical timepiece according to claim 6.

9. When the detection timing is delayed from the reference timing, the control circuit sets the braking force to the first braking force that causes the impulse wheel to collide with the other of the first struck portion and the second struck portion when the one motion of the impulse wheel is switched to the other motion.

9. The mechanical timepiece according to claim 7 or 8.

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